Robust electrochemical analysis of As(III) integrating with interference tests: A case study in groundwater

•Robust determination of As(III) in Togtoh water samples has been demonstrated.•The results were comparable to that obtained by ICP–AES.•No obvious interference was observed after a series of interference tests.•Robust stability was obtained in long-term measurements. In Togtoh region of Inner Mongolia, northern China, groundwater encountered high concentrations As contamination (greater than 50μgL−1) causes an increasing concern. This work demonstrates an electrochemical protocol for robust (efficient and accurate) determination of As(III) in Togtoh water samples using Au microwire electrode without the need of pretreatment or clean-up steps. Considering the complicated conditions of Togtoh water, the efficiency of Au microwire electrode was systematically evaluated by a series of interference tests, stability and reproducibility measurements. No obvious interference on the determination of As(III) was observed. Especially, the influence of humic acid (HA) was intensively investigated. Electrode stability was also observed with long-term measurements (70 days) in Togtoh water solution and under different temperatures (0–35°C). Excellent reproducibility (RSD:1.28%) was observed from different batches of Au microwire electrodes. The results obtained at Au microwire electrode were comparable to that obtained by inductively coupled plasma atomic emission spectroscopy (ICP–AES), indicating a good accuracy. These evaluations (efficiency, robustness, and accuracy) demonstrated that the Au microwire electrode was able to determine As(III) in application to real environmental samples.